Systems and methods for controlling arcing

ABSTRACT

The present disclosure relates to electrosurgical systems and methods for controlling electrical treatment energy in connection with electrical arcs. A method in accordance with the present disclosure includes providing electrical treatment energy to an instrument based on an indicated electrical energy level, accessing voltage signal values over time relating to voltage of the electrical treatment energy and/or current signal values over time relating to current of the electrical treatment energy, determining whether an arc generated by the instrument is an arc to be maintained or an arc to be extinguished based on a threshold value and at least one of the voltage signal values or the current signal values, and controlling the electrical treatment energy based on determining that the arc is an arc to be extinguished.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/900,377, filed on Feb. 20, 2018, now U.S. Pat. No. 11,045,247.

FIELD

The present disclosure generally relates to electrosurgical generators.More particularly, the present disclosure relates to electrosurgicalsystems and methods for controlling electrical treatment energy inconnection with electrical arcs.

BACKGROUND

An electrosurgical generator is used in surgical procedures to provideelectrical energy for treating the tissue of a patient. When anelectrosurgical probe or another electrosurgical instrument is connectedto the generator, the instrument can be used for cutting, coagulation,sealing, or fulgurating patient tissue with high frequency electricalenergy. During operation, electrical current from the generator isapplied by an electrode of the instrument to tissue and bodily fluids ofa patient.

In certain modes, the electrical energy provided by the electrosurgicalgenerator enables the instrument to create electrical arcs, which arebeneficial for certain procedures, such as fulguration of tissue.However, an electrical arc needs to be carefully controlled so that itachieves intended benefits without causing unintended harm. Therefore,it is desirable to control the electrical treatment energy provided bythe electrosurgical generator when an electrical arc is detected.Accordingly, there is continued interest in developing and improving thecontrol of electrical energy provided by an electrosurgical generator.

SUMMARY

The present disclosure relates to electrosurgical systems and methodsfor controlling electrical treatment energy in connection withelectrical arcs. As will be described herein in more detail, when anelectrosurgical generator provides electrical treatment energy to aninstrument and determines that the instrument is creating an arc thatshould be extinguished, such as a sustained arc to metal, theelectrosurgical generator controls the electrical treatment energy basedon that determination.

In accordance with aspects of the present disclosure, the presentdisclosure includes a method for controlling electrical treatment energyprovided to an instrument. The method includes providing electricaltreatment energy to the instrument based on an indicated electricalenergy level, accessing voltage signal values over time relating tovoltage of the electrical treatment energy and/or current signal valuesover time relating to current of the electrical treatment energy,determining whether an arc generated by the instrument is an arc to bemaintained or an arc to be extinguished based on a threshold value andat least one of: the voltage signal values or the current signal values,and controlling the electrical treatment energy based on determiningthat the arc is an arc to be extinguished.

In various embodiments, determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a magnitude of change inpeak-to-peak voltage of the electrical treatment energy over time beinggreater than the threshold value, where the threshold value changescorresponding to changes in the indicated electrical energy level.

In various embodiments, determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a magnitude of change inpeak-to-peak current of the electrical treatment energy over time beinggreater than the threshold value, where the threshold value changescorresponding to changes in the indicated electrical energy level.

In various embodiments, determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a normalized change inpeak-to-peak voltage of the electrical treatment energy over time beinggreater than the threshold value. The normalized change in peak-to-peakvoltage is a ratio of a magnitude of change in peak-to-peak voltage ofthe electrical treatment energy over one of: RMS voltage of theelectrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy. In thismanner, the threshold value does not change for changes in the indicatedelectrical energy level.

In various embodiments, determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a normalized change inpeak-to-peak current of the electrical treatment energy over time beinggreater than the threshold value. The normalized change in peak-to-peakcurrent is a ratio of a magnitude of change in peak-to-peak current ofthe electrical treatment energy over one of: RMS voltage of theelectrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy. In thismanner, the threshold value does not change for changes in the indicatedelectrical energy level.

In various embodiments, determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining apeak-to-peak voltage at a first time as a difference between a positivevoltage peak and a negative voltage peak of the electrical treatmentenergy at the first time, determining a peak-to-peak voltage at a secondtime as a difference between a positive voltage peak and a negativevoltage peak of the electrical treatment energy at a second time, thesecond time being after the first time, determining a change inpeak-to-peak voltage as an absolute value of a difference between thepeak-to-peak voltage at the first time and the peak-to-peak voltage atthe second time, determining an RMS voltage of the electrical treatmentenergy and an RMS current of the electrical treatment energy for thesecond time, determining a first normalized change in peak-to-peakvoltage as a ratio of the change in peak-to-peak voltage over the RMSvoltage, determining a second normalized change in peak-to-peak voltageas a ratio of the change in peak-to-peak voltage over the RMS current,accessing an impedance value indicative of an impedance of the arc, anddetermining that the arc is an arc to be extinguished when: the firstnormalized change in peak-to-peak voltage is greater than the thresholdand the impedance value is less than a first impedance threshold, or thesecond normalized change in peak-to-peak voltage is greater than asecond threshold and the impedance value is less than a second impedancethreshold.

In various embodiments, determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a crest factor of theelectrical treatment energy being greater than the threshold value.

In various embodiments, determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on an amount of variation increst factor of the electrical treatment energy over time being greaterthan the threshold value.

In various embodiments, determining that the arc is an arc to beextinguished includes determining voltage crest factor values over timebased on a ratio of one of positive voltage peak or negative voltagepeak of the electrical treatment energy over an RMS value of theelectrical treatment energy, determining current crest factor valuesover time based on a ratio of one of positive current peak or negativecurrent peak of the electrical treatment energy over an RMS value of theelectrical treatment energy, high-pass filtering the voltage crestfactor values to provide filtered voltage crest factor values, high-passfiltering the current crest factor values to provide filtered currentcrest factor values, combining absolute values of the filtered voltagecrest factor values with absolute values of the filtered current crestfactor values to provide combined crest factor values, low-passfiltering the combined crest factor values to provide resulting valuesindicative of an amount of variation in the voltage crest factor valuesand the current crest factor values, and determining that the arc is anarc to be extinguished when the resulting values exceed the thresholdvalue for a time duration threshold.

In accordance with aspects of the present disclosure, the presentdisclosure includes an electrosurgical generator for controllingelectrical treatment energy provided to an instrument. The generatorincludes one or more processors and at least one memory havinginstructions stored in the memory. The instructions, when executed bythe one or more processors, cause the generator to provide electricaltreatment energy to the instrument based on an indicated electricalenergy level, access voltage signal values over time relating to voltageof the electrical treatment energy and/or current signal values overtime relating to current of the electrical treatment energy, determinewhether an arc generated by the instrument is an arc to be maintained oran arc to be extinguished based on a threshold value and at least oneof: the voltage signal values or the current signal values, and controlthe electrical treatment energy based on determining that the arc is anarc to be extinguished.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining whether the arc isan arc to be maintained or an arc to be extinguished, to determine thatthe arc is an arc to be extinguished based on a magnitude of change inpeak-to-peak voltage of the electrical treatment energy over time beinggreater than the threshold value, wherein the threshold value changescorresponding to changes in the indicated electrical energy level.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining whether the arc isan arc to be maintained or an arc to be extinguished, to determine thatthe arc is an arc to be extinguished based on a magnitude of change inpeak-to-peak current of the electrical treatment energy over time beinggreater than the threshold value, wherein the threshold value changescorresponding to changes in the indicated electrical energy level.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining whether the arc isan arc to be maintained or an arc to be extinguished, to determine thatthe arc is an arc to be extinguished based on a normalized change inpeak-to-peak voltage of the electrical treatment energy over time beinggreater than the threshold value, wherein the normalized change inpeak-to-peak voltage is a ratio of a magnitude of change in peak-to-peakvoltage of the electrical treatment energy over one of: RMS voltage ofthe electrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy. In thismanner, the threshold value does not change for changes in the indicatedelectrical energy level.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining whether the arc isan arc to be maintained or an arc to be extinguished, to determine thatthe arc is an arc to be extinguished based on a normalized change inpeak-to-peak current of the electrical treatment energy over time beinggreater than the threshold value. The normalized change in peak-to-peakcurrent is a ratio of a magnitude of change in peak-to-peak current ofthe electrical treatment energy over one of: RMS voltage of theelectrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy. In thismanner, the threshold value does not change for changes in the indicatedelectrical energy level.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining whether the arc isan arc to be maintained or an arc to be extinguished, to determine apeak-to-peak voltage at a first time as a difference between a positivevoltage peak and a negative voltage peak of the electrical treatmentenergy at the first time, determine a peak-to-peak voltage at a secondtime as a difference between a positive voltage peak and a negativevoltage peak of the electrical treatment energy at a second time, thesecond time being after the first time, determine a change inpeak-to-peak voltage as an absolute value of a difference between thepeak-to-peak voltage at the first time and the peak-to-peak voltage atthe second time, determine an RMS voltage of the electrical treatmentenergy and an RMS current of the electrical treatment energy for thesecond time, determine a first normalized change in peak-to-peak voltageas a ratio of the change in peak-to-peak voltage over the RMS voltage,determine a second normalized change in peak-to-peak voltage as a ratioof the change in peak-to-peak voltage over the RMS current, access animpedance value indicative of an impedance of the arc, and determinethat the arc is an arc to be extinguished when: the first normalizedchange in peak-to-peak voltage is greater than the threshold value andthe impedance value is less than a first impedance threshold, or thesecond normalized change in peak-to-peak voltage is greater than asecond threshold value and the impedance value is less than a secondimpedance threshold.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining whether the arc isan arc to be maintained or an arc to be extinguished, to determine thatthe arc is an arc to be extinguished based on a crest factor of theelectrical treatment energy being greater than the threshold value.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining whether the arc isan arc to be maintained or an arc to be extinguished, to determine thatthe arc is an arc to be extinguished based on an amount of variation increst factor of the electrical treatment energy over time being greaterthan the threshold value.

In various embodiments, the instructions, when executed by the one ormore processors, cause the generator, in determining that the arc is anarc to be extinguished, to determine voltage crest factor values overtime based on a ratio of one of positive voltage peak or negativevoltage peak of the electrical treatment energy over an RMS value of theelectrical treatment energy, determine current crest factor values overtime based on a ratio of one of positive current peak or negativecurrent peak of the electrical treatment energy over an RMS value of theelectrical treatment energy, high-pass filter the voltage crest factorvalues to provide filtered voltage crest factor values, high-pass filterthe current crest factor values to provide filtered current crest factorvalues, combine absolute values of the filtered voltage crest factorvalues with absolute values of the filtered current crest factor valuesto provide combined crest factor values, low-pass filter the combinedcrest factor values to provide resulting values indicative of an amountof variation in the voltage crest factor values and the current crestfactor values, and determine that the arc is an arc to be extinguishedwhen the resulting values exceed the threshold value for a time durationthreshold.

In accordance with aspects of the present disclosure, the presentdisclosure includes an electrosurgical system. The system includes aninstrument and an electrosurgical generator. The electrosurgicalgenerator includes one or more processors and at least one memory havinginstructions stored in the memory. The instructions, when executed bythe one or more processors, cause the generator to provide electricaltreatment energy to the instrument based on an indicated electricalenergy level, access voltage signal values over time relating to voltageof the electrical treatment energy and/or current signal values overtime relating to current of the electrical treatment energy, determinewhether an arc generated by the instrument is an arc to be maintained oran arc to be extinguished based on a threshold value and at least oneof: the voltage signal values or the current signal values, and controlthe electrical treatment energy based on determining that the arc is anarc to be extinguished.

In accordance with aspects of the present disclosure, the presentdisclosure includes a method of controlling electrical treatment energyprovided to an instrument. The method includes providing electricaltreatment energy to the instrument based on an indicated electricalenergy level, accessing voltage signal values over time relating tovoltage of the electrical treatment energy or current signal values overtime relating to current of the electrical treatment energy, accessingan impedance based on the current and voltage signal values, accessing athreshold value corresponding to the impedance, extracting voltage andcurrent signals at three frequencies fH1, fH2, and fH3, determiningvoltage-to-current phase signals φH1, φH2, and φH3 based on voltage andcurrent signals at frequencies fH1, fH2, and fH3, respectively, low-passfiltering the phase signals φH1, φH2, and φH3 to provide φH1_filtered,φH2_filtered, and φH3_filtered, respectively, computing an arc detectiontrigger as: Trigger=|φH2_filtered−φ|+|φH2_filtered−φH3_filtered|,determining that an arc is an arc to be extinguished if the Triggervalue is greater than the threshold value, and controlling theelectrical treatment energy based on determining that the arc is an arcto be extinguished.

In accordance with aspects of the present disclosure, the presentdisclosure includes a method of controlling electrical treatment energyprovided to an instrument. The method includes providing electricaltreatment energy to the instrument based on user settings, performingcontrol feedback to achieve the user settings, accessing an absoluteintegrated error signal from the control feedback, determining that anarc is an arc to be extinguished based on the absolute integrated errorbeing greater than a threshold value, and controlling the electricaltreatment energy based on determining that the arc is an arc to beextinguished.

Further details and aspects of exemplary embodiments of the presentdisclosure are described in more detail below with reference to theappended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are described withreference to the accompanying drawings wherein:

FIG. 1 is a diagram of an exemplary electrosurgical system, inaccordance with aspects of the present disclosure;

FIG. 2 is a diagram illustrating arcing during a procedure, inaccordance with aspects of the present disclosure;

FIG. 3 is a block diagram of an exemplary electrosurgical generator, inaccordance with aspects of the present disclosure;

FIG. 4 is a flow diagram of an exemplary method of determining whetheran arc is an arc to be maintained or an arc to be extinguished based onchanges in peak-to-peak voltage or current over time, in accordance withaspects of the present disclosure;

FIG. 5 is a flow diagram of an exemplary method of determining whetheran arc is an arc to be maintained or an arc to be extinguished based onnormalized changes in peak-to-peak voltage or current over time, inaccordance with aspects of the present disclosure;

FIG. 6 is a flow diagram of an exemplary method of determining whetheran arc is an arc to be maintained or an arc to be extinguished based onnormalized changes in peak-to-peak voltage and impedance, in accordancewith aspects of the present disclosure;

FIG. 7 is a flow diagram of an exemplary method of determining whetheran arc is an arc to be maintained or an arc to be extinguished based oncrest factor, in accordance with aspects of the present disclosure;

FIG. 8 is a flow diagram of an exemplary method of determining whetheran arc is an arc to be maintained or an arc to be extinguished based onan amount of variation in crest factor over time, in accordance withaspects of the present disclosure;

FIG. 9 is a flow chart of one particular embodiment of the method ofFIG. 8, in accordance with aspects of the present disclosure;

FIG. 10 is a flow chart of one embodiment of controlling electricaltreatment energy when it is determined in the method of FIG. 9 that anarc is an arc to be extinguished, in accordance with aspects of thepresent disclosure;

FIG. 11 is a flow chart of a method of determining whether an arc is anarc to be extinguished based on phase differences between current andvoltage of the electric treatment energy at particular frequencies, inaccordance with aspects of the present disclosure; and

FIG. 12 is a flow chart of a method of determining whether an arc is anarc to be extinguished based on a feedback control parameter, inaccordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The present disclosure relates to electrosurgical systems and methodsfor controlling electrical treatment energy in connection withelectrical arcs. As will be described herein in more detail, in oneaspect of the present disclosure, when an electrosurgical generatorprovides electrical treatment energy to an instrument and determinesthat the instrument is creating an arc to be extinguished, theelectrosurgical generator controls the electrical treatment energy basedon that determination.

Where the term “approximately” is used herein in connection with aparameter having approximately a value, it is intended that theparameter can have exactly the value or can have another value whichdiffers from the value due to environmental factors such as noise or dueto hardware or software limitations such as, for example, number ofbits, processor speed, or interrupt priority.

Referring now to FIG. 1, there is shown a diagram of an exemplaryelectrosurgical system in accordance with aspects of the presentdisclosure. The system includes an electrosurgical instrument 10 havingone or more electrodes for treating tissue of a patient P. Theinstrument 10 may be either a monopolar type including one or moreactive electrodes (e.g., electrosurgical cutting probe, fulgurationelectrode(s), etc.) or a bipolar type including one or more active andreturn electrodes (e.g., electrosurgical sealing forceps).Electrosurgical energy is supplied to the instrument 10 by a generator20 via a supply line 12, allowing the instrument 10 to coagulate, seal,fulgurate, and/or otherwise treat tissue.

If the instrument 10 is a monopolar type instrument then energy may bereturned to the generator 20 through a return electrode (not shown)which may be disposed on the patient's body. In addition, the generator20 and the monopolar return electrode may be configured to monitorreturn electrode-to-patient contact to ensure that sufficient contactexists therebetween to mitigate chances of tissue damage. If theinstrument 10 is a bipolar type instrument, the return electrode isdisposed in proximity to the active electrode (e.g., on opposing jaws ofa bipolar forceps).

The generator 20 includes input controls (e.g., buttons, activators,switches, touch screen, etc.) for controlling the generator 20. Inaddition, the generator 20 may include one or more display screens forproviding the surgeon with a variety of output information (e.g.,intensity settings, treatment complete indicators, etc.). The controlsallow the surgeon to adjust power level of the electrical treatmentenergy and other parameters to achieve the desired treatment energysuitable for a particular procedure. It is also envisioned that theinstrument 10 may include input controls which may be redundant withcertain input controls of the generator 20. Placing the input controlsat the instrument 10 allows for easier and faster modification oftreatment energy parameters during the surgical procedure.

FIG. 2 is a diagram illustrating arcing during a monopolar procedureperformed by the electrosurgical instrument 2. A surgeon sets theelectrosurgical instrument 2 to a desired electrical treatment energylevel via the user interface of the generator and activates theelectrosurgical instrument 2 by depressing the activation switch 201,thus permitting electrosurgical treatment energy to be transmitted tothe tip 205 of the instrument 2. The surgeon then commences theelectrosurgical procedure by touching the tip 205 to the patient tissue.

In the illustrated example, arcing 215 to the tissue 225 occurs ahead ofthe tip 205 and can vaporize the tissue 225 before the probe 205 makescontact with the tissue 225. In various embodiments, arcs 215 form asthe tip 205 approaches the tissue 225 and extinguish once the tissuewithin range has been vaporized (e.g., tissue site 220). If the movementof the tip 205 in the direction 210 is slow compared to the power levelsetting of the generator, then the arc 215 vaporizes the tissue 220 andextinguishes before the tip 205 moves close enough to other tissue 225to reestablish an arc 215. If, on the other hand, the movement of thetip 205 is fast compared to the power level setting of the generator,then arcing may be reduced because of constant contact between the tip205 and the tissue 225, or arcing may be maintained at a consistentlevel. Accordingly, different arcing situations may occur during anelectrosurgical procedure. Additionally, various types of proceduresother than tissue vaporization may involve arcing, such as tissuecoagulation. Various ways of controlling an electrosurgical generator inarcing situations are disclosed in U.S. Pat. No. 7,651,492 and in U.S.Pat. No. 9,498,275. The entire contents of both of these U.S. patentsare hereby incorporated by reference herein.

An electrosurgical generator in accordance with the present disclosureis enabled to detect arcs that should be extinguished, such as sustainedarcs formed to metal, and to control the electrosurgical treatmentenergy in that situation. For example, various types of procedures mayinvolve multiple instruments at the same surgical site, such as usingforceps to grasp tissue and then using arcs from an electrosurgicalprobe to fulgurate the tissue grasped by the forceps. In this example,arcs may form to the forceps. If an electrosurgical generator is unableto determine that such an arc should be extinguished, theelectrosurgical generator may operate to sustain the arc to metal andcause unintended harm to surrounding tissue. Accordingly, disclosedbelow are systems and methods for determining that an arc is an arc tobe extinguished.

FIG. 3 shows a schematic block diagram of one embodiment of a generator300, which is configured to output electrosurgical energy, and generatorcomponents. The generator 300 includes a user interface 305, acontroller 324, a power supply 327, and an output stage 328. The powersupply 327 may be a direct current high voltage power supply and may beconnected to an AC source (e.g., line voltage). The power supply 327provides high voltage DC power to an output stage 328, which thenconverts high voltage DC power into electrosurgical alternating currentand provides the electrosurgical energy to the active terminal 330. Thealternating current is returned to the output stage 328 via the returnterminal 332. The output stage 328 is configured to operate in aplurality of modes, during which the generator 300 outputs electricaltreatment energy having specific power levels, peak voltages, crestfactors, etc. In other embodiments, the generator 300 may be based onother types of suitable power supply or power conversion topologies.

The controller 324 includes a processor 325 (e.g., a microprocessor)operably connected to a memory 326, which may include transitory typememory (e.g., RAM) and/or non-transitory type memory (e.g., flash mediaand disk media). In various embodiments, the controller 324 may furtherinclude a field-programmable gate array (FPGA) for performing real-timeanalysis of the delivered current and/or voltage waveforms. Theprocessor 325 includes an output port that is operably connected to thepower supply 327 and/or output stage 328, allowing the processor 325 tocontrol the output of the generator 300 according to either open- and/orclosed-loop control schemes. Those skilled in the art will appreciatethat the processor 325 may be substituted by any logic processor (e.g.,control circuit) adapted to perform the calculations and/or set ofinstructions discussed herein.

In various embodiments, the generator 300 implements a closed-loopfeedback control system, in which sensors measure a variety of tissueand generator output properties (e.g., impedance, output power, currentand/or voltage, etc.), and provide feedback to the controller 324. Thecontroller 324 then signals the power supply 327 and/or output stage328, which then adjusts the DC power supply and/or output stage,respectively. The controller 324 also receives input signals from theuser interface 305 of the generator 300. The controller 324 utilizesinput signals received through the user interface 305 to adjust poweroutputted by the generator 300 and/or performs other control functionsthereon. According to the present disclosure, an operator may input adesired power level setting via the user interface 305.

The generator 300 according to the present disclosure includes an RFcurrent sensor 380 and an RF voltage sensor 370. The RF current sensor380 is coupled to the active terminal 330 and provides measurements ofthe RF current supplied by the output stage 328. The RF voltage sensor370 is coupled to the active and return terminals 330 and 332, andprovides measurements of the RF voltage supplied by the output stage328. In various embodiments, the RF voltage and current sensors 370 and380 may be coupled to active lead 331 and return lead 333, whichinterconnect the active and return terminals 330 and 332 to the outputstage 328, respectively.

The RF voltage and current sensors 370 and 380 provide the sensed RFvoltage and current signals, respectively, to analog-to-digitalconverters (ADCs) 302. The ADCs 302 sample the sensed RF voltage andcurrent signals and provide digital samples of the sensed RF voltage andcurrent signals to the controller 324, which then may adjust the outputof the power supply 327 and/or the output stage 328 in response to thedigital samples of the sensed RF voltage and current signals. In variousembodiments, the digital samples may be stored in the memory 326 untilthey are needed and may be deleted from the memory 326 when they are nolonger needed.

In various embodiments, the controller 324 is adapted to determinevarious parameters based on the voltage and current signals values,including tissue impedance, crest factors, phase differences between thevoltage and current signals, phase differences between certain frequencycomponents of the voltage and current signals, peak voltage, peakcurrent, RMS (root mean squared) voltage, RMS current, and averagepower, among other parameters. In various embodiments, one or more suchparameters can be determined by separate hardware circuitry (not shown)rather than by the controller 324. Implementations of such parametercalculations by processor instructions and/or by hardware circuitry areknown to persons skilled in the art. Usage of such parameters will bedescribed below in connection with determining whether an arc is an arcto be maintained or an arc to be extinguished.

Referring now to FIG. 4, there is shown a flow diagram of an exemplarymethod of determining whether an arc is an arc to be maintained or anarc to be extinguished based on changes in peak-to-peak voltage orcurrent over time. It has been found that a sustained arc to metalresults in larger changes in peak-to-peak voltage or current over timecompared to changes in peak-to-peak voltage or current for an arc totissue. The magnitude of change in peak-to-peak voltage or current overtime can be compared to a threshold value to determine whether the arcis an arc to be maintained or an arc to be extinguished, such as asustained arc to metal. However, the magnitude of change in thepeak-to-peak voltage or current varies for different power settinglevels. Accordingly, different threshold values are needed for differentpower setting levels.

At step 402, the generator provides electrical treatment energy to theinstrument based on an electrical energy level indicated by the surgeon,which can be specified using the user interface (305, FIG. 3) of thegenerator. At step 404, the generator accesses voltage signal valuesover time relating to voltage of the electrical treatment energy orcurrent signal values over time relating to current of the electricaltreatment energy. As described above, such signal values can be digitalsamples stored in the memory (326, FIG. 3) of the controller. In variousembodiments, the signal values need not be stored in the memory of acontroller and can be stored in a buffer circuit. At step 406, thegenerator accesses a threshold value corresponding to the electricalenergy level indicated by the surgeon. In various embodiments, a singlethreshold value can correspond to one or more electrical energy levels.The threshold values can be stored in and accessed from the memory ofthe controller.

At step 408, the generator determines, based on the signal values, amagnitude of change in peak-to-peak voltage of the electrical treatmentenergy over time or a magnitude of change in peak-to-peak current of theelectrical treatment energy over time. As persons skilled in the artwill understand, a magnitude is a positive value so that the magnitudeof the change is a positive value regardless of the direction of change.In various embodiments, the generator includes a processor (325, FIG. 3)and the magnitude of change in peak-to-peak voltage or current can bedetermined at processor interrupts as the change in peak-to-peak voltageor current from one interrupt to the next interrupt. In variousembodiments, the change in peak-to-peak voltage or current can bedetermined over another period of time. At step 410, if the magnitude ofchange in peak-to-peak voltage of the electrical treatment energy overtime is greater than the threshold value, or if the magnitude of changein peak-to-peak current of the electrical treatment energy over time isgreater than the threshold value, the generator determines that the arcis an arc to be extinguished. In various embodiments, the determinationat step 410 considers the impedance of the arc, as determined from thevoltage and current signal values. An example is described in connectionwith FIG. 6.

Then at step 412, the generator controls the electrical treatment energybased on determining that the arc is an arc to be extinguished. Invarious embodiments, the control at step 412 can include decreasing theelectrical treatment energy for a predetermined time duration.

Referring now to FIG. 5, there is shown a flow diagram of an exemplarymethod of determining whether an arc is an arc to be maintained or anarc to be extinguished based on normalized changes in peak-to-peakvoltage or current over time. The method of FIG. 5 is a variation of themethod of FIG. 4 in which the magnitude of changes in peak-to-peakvoltage or current is normalized so that the threshold value is notdependent on the power setting level. Accordingly, only one singlethreshold value is needed.

At step 502, the generator provides electrical treatment energy to theinstrument based on an electrical energy level indicated by the surgeon,which can be specified using the user interface (305, FIG. 3) of thegenerator. At step 504, the generator accesses voltage signal valuesover time relating to voltage of the electrical treatment energy orcurrent signal values over time relating to current of the electricaltreatment energy. As described above, such signal values can be digitalsamples stored in the memory (326, FIG. 3) of the controller or signalvalues stored in a buffer circuit. At step 506, the generator accessesthe threshold value. As mentioned above, there is a single thresholdvalue regardless of the electrical energy level set by the surgeon. Invarious embodiments, the threshold value can be stored in and accessedfrom the memory of the controller. In various embodiments, the thresholdvalue can be hard coded into a processor instruction.

At step 508, the generator determines, based on the signal values, anormalized magnitude of change in peak-to-peak voltage of the electricaltreatment energy over time or a normalized magnitude of change inpeak-to-peak current of the electrical treatment energy over time. Thenormalized magnitude of change is the magnitude of change divided by aquantity that scales with the electrical energy level. In variousembodiments, the normalization parameter can be RMS voltage of theelectrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy.Accordingly, the normalized magnitude of change in peak-to-peak voltagewould be the magnitude of change in peak-to-peak voltage divided by oneof RMS voltage, RMS current, or average power. In the same way, thenormalized magnitude of change in peak-to-peak current would be themagnitude of change in peak-to-peak current divided by one of RMSvoltage, RMS current, or average power.

At step 510, if the normalized magnitude of change in peak-to-peakvoltage of the electrical treatment energy over time is greater than thethreshold value, or if the normalized magnitude of change inpeak-to-peak current of the electrical treatment energy over time isgreater than the threshold value, the generator determines that the arcis an arc to be extinguished. As discussed above in connection with FIG.4, in various embodiments, the determination at step 510 considers theimpedance of the arc, as determined from the voltage and current signalvalues. An example is described in connection with FIG. 6.

Then at step 512, the generator controls the electrical treatment energybased on determining that the arc is an arc to be extinguished. Invarious embodiments, the control at step 512 can include decreasing theelectrical treatment energy for a predetermined time duration.

Referring now to FIG. 6, there is shown a flow chart of an exemplarymethod of determining whether an arc is an arc to be maintained or anarc to be extinguished based on normalized changes in peak-to-peakvoltage over time and based on impedance.

At step 602, the generator provides electrical treatment energy to theinstrument based on an electrical energy level indicated by the surgeon,which can be specified using the user interface (305, FIG. 3) of thegenerator. At step 604, the generator accesses voltage signal valuesover time relating to voltage of the electrical treatment energy orcurrent signal values over time relating to current of the electricaltreatment energy. As described above, such signal values can be digitalsamples stored in the memory (326, FIG. 3) of the controller or signalvalues stored in a buffer circuit. At step 606, the generator accessesfour threshold values—a first threshold value (Th1), a first impedancethreshold (Z1), a second threshold value (Th2), and a second impedancethreshold (Z2). Based on normalization in the following steps, thesethreshold values do not depend on electrical treatment energy level andcan be applied regardless of the electrical treatment energy level setby the surgeon. In various embodiments, the threshold values can bestored in and accessed from the memory of the controller. In variousembodiments, the threshold value can be hard coded into processorinstructions.

At step 608, the generator determines, based on the voltage signalvalues, the magnitude of change in peak-to-peak voltage between a firsttime and a second time after the first time (dVpp). At step 610, thegenerator determines, based on the voltage and current signal values,RMS voltage (Vrms) and RMS current (Irms) of the electrical treatmentenergy at the second time, and arc impedance at the second time. Then atstep 612, the generator determines two normalized parameters—dVpp/Vrmsand dVpp/Irms. In various embodiments, the parameter dVpp/Irms can bescaled.

At step 614, the generator determines that the arc is an arc to beextinguished if:

(dVpp/Vrms>Th1) and (impedance<Z ₁)

or

(dVpp/Irms>Th2) and (impedance<Z ₂).

In various embodiments, Z₁ can be characterized as an impedancethreshold that is used to determine whether to use Vrms or Irms tonormalize the magnitude of change in peak-to-peak voltage dVpp, and Z₂can be described as an impedance threshold above which the generatorwill not intentionally extinguish an arc. In various embodiments, Z₁ is1350 ohms and Z₂ is 3000 ohms. In various embodiments, the impedancethresholds can have other values. In various embodiments, the values ofZ₁ and Z₂ can be derived from analyzing voltage and current datarelating to arcs.

Then at step 616, the generator controls the electrical treatment energybased on determining that the arc is an arc to be extinguished. Invarious embodiments, the control at step 616 can include decreasing theelectrical treatment energy for a predetermined time duration. Invarious embodiments, the control at step 616 can include decreasing theelectrical treatment energy for a time duration that is computed or thatis based on sensed electrical data, such as voltage, current, and/orimpedance data. For example, the electrical treatment energy can bedecreased until the impedance rises and indicates an open circuitcondition, such as an impedance greater than 7,000 ohms. In variousembodiments, the control at step 616 can include turning off the energydelivery for a predetermined or computed time duration, or for a timeduration that is based on sensed electrical data.

Accordingly, described above in connection with FIGS. 4-6 are methodsfor determining whether an arc is an arc to be maintained or an arc tobe extinguished based on magnitude of changes in peak-to-peak voltage orcurrent. The determinations can be performed by a processor executinginstructions, and can be performed as instructions executed duringprocessor interrupts. In various embodiments, the determinations can beperformed approximately every 0.5 milliseconds. In various embodiments,the threshold values of FIGS. 4-6 can be obtained by analyzing empiricaldata corresponding to arcs to tissue and empirical data corresponding toarcs to non-tissue, such as metal. The empirical data will reveal theboundaries between parameter values corresponding to an arc to bemaintained and the parameter values corresponding to an arc to beextinguished, such as a sustained arc to metal. Because differentgenerators will be implemented differently, the threshold values may bedependent on the particular model or brand of the generator. In light ofthe methods disclosed herein, obtaining empirical data and determiningthe threshold values for different generators are within the abilitiesand competencies of persons skilled in the art. This manner ofdetermining threshold values also applies to FIGS. 7-12 below.

The following will now describe a method of determining whether an arcis an arc to be maintained or an arc to be extinguished based on crestfactors. As used herein, and as understood in the art, crest factorrefers to a ratio of a peak value over an RMS value. In variousembodiments, the peak value can be a positive peak voltage, a negativepeak voltage, a positive peak current, or a negative peak current. Invarious embodiments, the RMS value can be RMS voltage (Vrms) or RMScurrent (Irms). Various combinations of these peak values and RMS valuesare all contemplated to be crest factors. With reference also to FIG. 3,in various embodiments, a crest factor value can be determined by thecontroller 324 based on the current signals and the voltage signalssensed by the current and voltage sensors 370, 380.

Referring now to FIG. 7, there is shown a flow diagram of an exemplarymethod of determining whether an arc is an arc to be maintained or anarc to be extinguished based on crest factor. It has been found that asustained arc to non-tissue, such as an arc to metal, results in largercrest factor compared to a crest factor for an arc to tissue. In variousembodiments, the crest factor value can be compared to a threshold valueto determine whether the arc is an arc that should be maintained or anarc that should be extinguished, such as an arc to metal. Because acrest factor is defined by an RMS value, which scales with differentpower setting levels, crest factor inherently does not depend on thepower setting level. Accordingly, the same threshold value can beapplied to different power setting levels.

At step 702, the generator provides electrical treatment energy to theinstrument based on an electrical energy level indicated by the surgeon,which can be specified using the user interface (305, FIG. 3) of thegenerator. At step 704, the generator accesses voltage signal valuesover time relating to voltage of the electrical treatment energy orcurrent signal values over time relating to current of the electricaltreatment energy. As described above, such signal values can be digitalsamples stored in the memory (326, FIG. 3) of the controller or signalvalues stored in a buffer circuit. At step 706, the generator accessesthe threshold value. As mentioned above, there is a single thresholdvalue regardless of the electrical energy level set by the surgeon. Invarious embodiments, the threshold value can be stored in and accessedfrom the memory of the controller. In various embodiments, the thresholdvalue can be hard coded into a processor instruction.

At step 708, the generator determines a crest factor value based on thesignal values. As mentioned above, the crest factor can be based on apeak value that is one of a positive peak voltage, a negative peakvoltage, a positive peak current, or a negative peak current, and can bebased on an RMS value that is one of RMS voltage (Vrms) or RMS current(Irms). At step 710, if the crest factor value is greater than thethreshold value, the generator determines that the arc is an arc to beextinguished. In various embodiments, step 710 can consider impedance inmaking the determination.

Then at step 712, the generator controls the electrical treatment energybased on determining that the arc is an arc to be extinguished. Invarious embodiments, the control at step 712 can include decreasing theelectrical treatment energy for a predetermined time duration.

Referring now to FIG. 8, there is shown a flow diagram of an exemplarymethod of determining whether an arc is an arc to be maintained or anarc to be extinguished based on an amount of variation in crest factorover time. It has been found that a sustained arc to non-tissue, such asan arc to metal, results in larger variations in crest factor over timecompared to variations in crest factor for an arc to tissue. The amountof variation in crest factor value can be compared to a threshold valueto determine whether the arc is an arc to be maintained or an arc to beextinguished. Because amount of variation is a metric that does notdepend on the power setting level, the same threshold value can beapplied to different power setting levels.

At step 802, the generator provides electrical treatment energy to theinstrument based on an electrical energy level indicated by the surgeon,which can be specified using the user interface (305, FIG. 3) of thegenerator. At step 804, the generator accesses voltage signal valuesover time relating to voltage of the electrical treatment energy orcurrent signal values over time relating to current of the electricaltreatment energy. As described above, such signal values can be digitalsamples stored in the memory (326, FIG. 3) of the controller or signalvalues stored in a buffer circuit. At step 806, the generator accessesthe threshold value. As mentioned above, there is a single thresholdvalue regardless of the electrical energy level set by the surgeon. Invarious embodiments, the threshold value can be stored in and accessedfrom the memory of the controller. In various embodiments, the thresholdvalue can be hard coded into a processor instruction.

At step 808, the generator determines crest factor values over timebased on the signal values. As mentioned above, the crest factor can bebased on a peak value that is one of a positive peak voltage, a negativepeak voltage, a positive peak current, or a negative peak current, andcan be based on an RMS value that is one of RMS voltage (Vrms) or RMScurrent (Irms). At step 810, the generator determines the amount ofvariation in the crest factor values. There are various wayscontemplated for determining amount of variation. For example, withoutlimitation, an amount of variation can be determined using statisticalmeasures, such as standard deviation. Another way to determine amount ofvariation is by use of filters, as explained in connection with FIG. 9.Other ways of determining amount of variation are contemplated to bewithin the scope of the present disclosure.

At step 812, if the amount of variation in crest factor is greater thanthe threshold value, the generator determines that the arc is an arc tobe extinguished. Then at step 814, the generator controls the electricaltreatment energy based on determining that the arc is an arc to beextinguished. In various embodiments, the control at step 814 caninclude decreasing the electrical treatment energy for a predeterminedtime duration.

FIG. 9 shows a flow chart of one particular embodiment of the method ofFIG. 8, for determining an amount of variation in crest factor valuesover time. In particular, FIG. 9 shows one way to determine amount ofvariation using high-pass and low-pass filters.

At step 902, the generator provides electrical treatment energy to theinstrument based on an electrical energy level indicated by the surgeon,which can be specified using the user interface (305, FIG. 3) of thegenerator. At step 904, the generator accesses voltage signal valuesover time relating to voltage of the electrical treatment energy andcurrent signal values over time relating to current of the electricaltreatment energy. As described above, such signal values can be digitalsamples stored in the memory (326, FIG. 3) of the controller or signalvalues stored in a buffer circuit. At step 906, the generator accessesthe threshold value. As mentioned above, there is a single thresholdvalue regardless of the electrical energy level set by the surgeon. Invarious embodiments, the threshold value can be stored in and accessedfrom the memory of the controller. In various embodiments, the thresholdvalue can be hard coded into a processor instruction.

At step 908, the generator determines crest factor values over timebased on the signal values, including positive current crest factor(Ipos_CF) based on positive peak current, negative current crest factor(Ineg_CF) based on negative peak current, positive voltage crest factor(Vpos_CF) based on positive peak voltage, and negative voltage crestfactor (Vneg_CF) based on negative peak voltage, of the electricaltreatment energy over time. At step 910, the generator high-pass filtersIpos_CF over time to provide Ipos_CF_filtered, high-pass filters Ineg_CFover time to provide Ineg_CF_filtered, high-pass filters Vpos_CF overtime to provide Vpos_CF filtered, and high-pass filters Vneg_CF overtime to provided Vneg_CF_filtered. The high-pass filtering removes a DCcomponent from the crest factors so that the filtered crest factorvalues represent the crest factor variations centered at zero. Thus, thehigh-pass filtering passes the changes so that the result is azero-centered pattern of pulses which represent each change in crestfactor. In various embodiments, the high pass filter can be a digitalfirst order, recursive filter with a cut-off frequency around 500 kHz.

At step 912, the absolute values of the four filtered crest factors areadded together. In particular, each of the filtered crest factors havemultiple values, such as N values, e.g., Ipos_CF_filtered[n],Ineg_CF_filtered[n], Vpos_CF_filtered[n], and Vneg_CF_filtered[n], forn=1 . . . N. For each n, the generator determines combined crest factorvalues:

CF_(var)[n]=|I _(pos_CF_filtered)[n]|+|I _(neg_CF_filtered)[n]|V_(pos_CF_filtered)[n]+|V _(neg_CF_filtered)[n]|.

In this way, the variations from each of the filtered crest factors arecombined, and the resulting values CF_(var) capture the variations amongthe four crest factors.

At step 914, the values CF_(var) are low-pass filtered. Because CF_(var)is as sum of absolute values, all values of CF_(var) are positive.Accordingly, the CF_(var) sequence will have a DC component, andlow-pass filtering the CF_(var) sequence provides the DC component. ThisDC component of CF_(var) represents the amount of variation in the crestfactors. In various embodiments, design of the low-pass filter involvesa balancing of false-positive detection and detection time. For example,a longer detection time leads to fewer false-positives in determiningthat an arc should be extinguished, whereas a shorter detection timeleads to more false-positives in determining that an arc should beextinguished. In various embodiments, in balancing these factors, thelow-pass filter is a digital second order, recursive filter having 5milliseconds to 99% rise time.

At step 916, if the amount of variation in crest factors is greater thanthe threshold value for at least a detection time threshold, thegenerator determines that the arc is an arc to be extinguished. Invarious embodiments, the threshold value is 0.15 and the detection timethreshold is 15 milliseconds. Then at step 918, the generator controlsthe electrical treatment energy based on determining that the arc is anarc to be extinguished. The control in step 918 is described in moredetail below with respect to FIG. 10. In various embodiments, thedetermination at step 916 considers the impedance of the arc, asdetermined from the voltage and current signal values. In variousembodiments, at step 916, the generator does not determine that the arcis an arc to be extinguished if the arc impedance is greater than 15,000ohms.

Although the embodiment of FIG. 9 involves using four crest factors, invarious embodiments, less than four crest factors can be used. Invarious embodiments, the operation of FIG. 9 uses only a single currentcrest factor and a single voltage crest factor. In various embodiments,the single current crest factor can be the larger of the positivecurrent crest factor and the negative current crest factor. In variousembodiments, the single voltage crest factor can be the larger of thepositive voltage crest factor and the negative voltage crest factor.

Referring now to FIG. 10, there is shown a flow chart of one embodimentof controlling electrical treatment energy when it is determined in themethod of FIG. 9 that an arc is an arc to be extinguished. Theillustrated embodiment is exemplary and non-limiting, and other ways arecontemplated for controlling electrical treatment energy when there isan arc to be extinguished.

At step 1002, when it is determined that an arc is an arc to beextinguished, the generator decreases the electrical treatment energyprovided to the instrument. In various embodiments, the electricaltreatment energy is deceased to a low energy level, such as 5 Watts. Invarious embodiments, the low energy level can be another level, such azero watts. In various embodiments, the low energy level can be apercentage of the power level set by the surgeon, such as 10% of theindicated power level, or another percentage. In step 1004, thegenerator holds the electrical treatment energy at the decreased levelfor a predetermined hold duration to extinguish the arc. In variousembodiments, the predetermined hold duration can be 25 milliseconds, 60milliseconds, or another duration.

At step 1006, the generator resets all crest factor filters, and at step1008, the generator restores the electrical treatment energy to theenergy level indicated by the surgeon. At step 1010, the generatorprevents re-detection of an arc to be extinguished for a predeterminedre-detection hold duration. In one embodiment, the re-detection holdduration is 5 milliseconds. Then at step 1012, after the re-detectionhold duration elapses, the generator permits re-detection of an arc tobe extinguished.

Accordingly, described above in connection with FIGS. 7-10 are systemsand methods for determining whether an arc is an arc to be maintained oran arc to be extinguished based on crest factors. The determinations canbe performed by a processor executing instructions, and can be performedas instructions executed during processor interrupts. In variousembodiments, the determinations can be performed approximately every0.44 milliseconds, every 15 milliseconds, or at another time interval.Comparing the crest factor methodology of FIG. 10 to the change inpeak-to-peak methodology of FIGS. 4-6, the crest factor methodology ismeaningfully slower. This slower operation of the crest factormethodology of FIG. 10 depends in large part on the amount of timerequired for the high-pass and low-pass filters to operate. Whereas thecrest factor methodology of FIG. 10 requires filters, the change inpeak-to-peak methodology of FIGS. 4-6 does not require any filtering.

In various embodiments, the threshold values and hold durations of FIGS.7-10 can be obtained by analyzing empirical data corresponding to arcsto tissue and empirical data corresponding to arcs to metal. Theempirical data will reveal the boundaries between parameter valuescorresponding to an arc to be maintained and the parameter valuescorresponding to an arc to be extinguished. Because different generatorswill be implemented differently, the threshold values may be dependenton the particular model or brand of the generator. In light of themethods disclosed herein, obtaining empirical data and determining thethreshold values and hold durations for different generators are withinthe abilities and competencies of persons skilled in the art.

The following description with respect to FIGS. 11 and 12 describemethods of determining whether an arc is an arc to be maintained or anarc to be extinguished, such as a sustained arc to metal.

FIG. 11 is a flow chart of a method of determining that an arc is an arcthat should be extinguished based on phase differences between currentand voltage of the electric treatment energy at particular frequencies.With reference to FIG. 3, the particular frequencies include thefundamental frequency of the electrical treatment energy waveform outputby the output stage 328, which will be denoted as f_(H1). The otherfrequencies relate to the output stage 328. As described above, thepower supply 327 provides high voltage DC power to an output stage 328,which then converts high voltage DC power into electrosurgicalalternating current. Accordingly, the output stage 328 includes aresonant inverter. In various embodiments, the particular frequenciesinclude a first resonant frequency f_(H2) of the inverter circuit whenthere is no load (i.e., open circuit), and a second resonant frequencyf_(H3) of the inverter circuit when there is a short circuit load.

It has been found that during an arc that should be extinguished, suchas a sustained arc to metal, certain phase information for the threefrequencies f_(H1), f_(H2), and f_(H3), correlate to such an arc. Inparticular, the voltage to current phase difference at frequency finwill be denoted as φ_(H1), the voltage to current phase difference atfrequency f_(H2) will be denoted as φH2, and the voltage to currentphase difference at frequency fin will be denoted as φ_(H3). It has beenfound, also, that the threshold value for arc differentiation inaccordance with this methodology varies depending on the impedancedetermined from the current and voltage signals, which relates to thematched load of the inverter circuit (the load the inverter develops atits highest, most efficient power output). Accordingly, there aremultiple threshold values corresponding to different impedance values.

At step 1102, the generator provides electrical treatment energy to theinstrument based on an electrical energy level indicated by the surgeon,which can be specified using the user interface (305, FIG. 3) of thegenerator. At step 1104, the generator accesses voltage signal valuesover time relating to voltage of the electrical treatment energy orcurrent signal values over time relating to current of the electricaltreatment energy. As described above, such signal values can be digitalsamples stored in the memory (326, FIG. 3) of the controller or signalvalues stored in a buffer circuit. At step 1106, the generator accessesor determines an impedance based on the current and voltage signalvalues, and accesses a threshold value corresponding to the impedance.In various embodiments, the threshold values can be stored in andaccessed from the memory of the controller.

At step 1108, the generator extracts voltage and current signals atfrequencies f_(H1), f_(H2), and f_(H3). At step 1110, the generatordetermines voltage-to-current phase signals φ_(H1), φ_(H2), and φ_(H3),based on the voltage and current signals at frequencies f_(H1), f_(H2),and f_(H3), respectively. In various embodiments, the operations ofsteps 1108 and 1110 can be performed based on Goertzel filters, DiscreteFourier Transforms (DFT), Fast Fourier Transforms (FFT), or narrowbandfilters. At step 1112, the generator low-pass filters the phase signalsf_(H1), f_(H2), and f_(H3) to provide φ_(H1_filtered), φ_(H2_filtered),and φ_(H3_filtered), respectively. At step 1114, the arc detectiontrigger value is computed as:

Trigger=|φ_(H2_filtered)−φ_(H1_filtered)|+|φ_(H2_filtered)−φ_(H3_filtered)|.

In various embodiments, the trigger can be described as the magnitude ofthe change in phase between components H2 and H3 in relation to thefundamental drive frequency component H1. At step 1116, the generatordetermines that an arc is an arc to be extinguished if the Trigger valueis greater than the threshold value.

And at step 1118, the generator controls the electrical treatment energybased on determining that an arc is an arc to be extinguished. Invarious embodiments, the generator can perform a control proceduresimilar to that shown in FIG. 10, including decreasing the electricaltreatment energy for a predetermined hold duration to extinguish thearc, resetting all filters, restoring the electrical treatment energy tothe energy level indicated by the surgeon, preventing re-detection ofthe arc for a predetermined re-detection hold duration, and thenpermitting re-detection of an arc after the re-detection hold durationelapses.

Referring now to FIG. 12, there is shown a method of determining that anarc should be extinguished based on a feedback control parameterreferred to herein as absolute integrated error. Referring also to FIG.3, the generator 300 implements a closed-loop feedback control system,in which sensors provide feedback to the controller 324. The controller324 then signals the power supply 327 and/or output stage 328, whichthen adjusts the DC power supply and/or output stage, respectively. Inthe feedback operation, an error between an intended parameter value andthe actual parameter value is tracked over time by computing theabsolute value of the error and integrating it over time. In variousembodiments, the integration can be performed by a leaky integrator. Invarious embodiments, the leaky integrator can be implemented by a lowpass filter. This integrated value is referred to herein as the absoluteintegrated error. The absolute integrated error rises while the controlsystem is not at target (e.g., target voltage, current or power) andgoes to zero when on target. It has been found that the absoluteintegrated error signal of the generator control system is correlatedwith the presence of an arc that should be extinguished. In particular,arc behavior causes rapid changes in the impedance presented to thegenerator 300, and it is more difficult for the generator to track theserapid changes, thereby causing the absolute integrated error to riseduring sustained arcing to metal.

At step 1202, the generator provides electrical treatment energy to theinstrument based on user settings. At step 1204, the generator performscontrol feedback to achieve the user settings. At step 1206, thegenerator accesses the absolute integrated error signal from the controlfeedback. At step 1208, the generator determines that an arc is an arcto be extinguished based on the absolute integrated error being greaterthan a threshold value. And at step 1210, the generator controls theelectrical treatment energy based on determining that an arc is an arcbe extinguished. In various embodiments, the control at step 1210 caninclude decreasing the electrical treatment energy for a predeterminedtime duration.

Accordingly, described here are systems and methods for controllingelectrical treatment energy to determine that an arc is an arc thatshould be extinguished. The embodiments disclosed herein are examples ofthe disclosure and may be embodied in various forms. For instance,although certain embodiments herein are described as separateembodiments, each of the embodiments herein may be combined with one ormore of the other embodiments herein. Specific structural and functionaldetails disclosed herein are not to be interpreted as limiting, but as abasis for the claims and as a representative basis for teaching oneskilled in the art to variously employ the present disclosure invirtually any appropriately detailed structure. Like reference numeralsmay refer to similar or identical elements throughout the description ofthe figures.

The phrases “in an embodiment,” “in embodiments,” “in variousembodiments,” “in some embodiments,” or “in other embodiments” may eachrefer to one or more of the same or different embodiments in accordancewith the present disclosure. A phrase in the form “A or B” means “(A),(B), or (A and B).” A phrase in the form “at least one of A, B, or C”means “(A); (B); (C); (A and B); (A and C); (B and C); or (A, B, andC).”

It should be understood that the foregoing description is onlyillustrative of the present disclosure. Various alternatives andmodifications can be devised by those skilled in the art withoutdeparting from the disclosure. Accordingly, the present disclosure isintended to embrace all such alternatives, modifications and variances.The embodiments described with reference to the attached drawing figuresare presented only to demonstrate certain examples of the disclosure.Other elements, steps, methods, and techniques that are insubstantiallydifferent from those described above and/or in the appended claims arealso intended to be within the scope of the disclosure.

The systems and methods described herein utilize one or more controllersto receive information and transform the received information togenerate an output. The controller may include any type of computingdevice, computational circuit, or any type of processor or processingcircuit capable of executing a series of instructions that are stored ina memory. The controller may include multiple processors and/ormulticore central processing units (CPUs) and may include any type ofprocessor, such as a microprocessor, digital signal processor,microcontroller, programmable logic device (PLD), field programmablegate array (FPGA), or the like. The controller may also include a memoryto store data and/or instructions that, when executed by the one or moreprocessors, causes the one or more processors to perform one or moremethods and/or algorithms.

The controller(s) may implement methods, programs, algorithms or codesusing a programming language or computer program. The terms “programminglanguage” and “computer program,” as used herein, each include anylanguage used to specify instructions to a computer, and include (but isnot limited to) the following languages and their derivatives:Assembler, Basic, Batch files, BCPL, C, C+, C++, Delphi, Fortran, Java,JavaScript, machine code, operating system command languages, Pascal,Perl, PL1, scripting languages, Visual Basic, metalanguages whichthemselves specify programs, and all first, second, third, fourth,fifth, or further generation computer languages. Also included aredatabase and other data schemas, and any other meta-languages. Nodistinction is made between languages which are interpreted, compiled,or use both compiled and interpreted approaches. No distinction is madebetween compiled and source versions of a program. Thus, reference to aprogram, where the programming language could exist in more than onestate (such as source, compiled, object, or linked) is a reference toany and all such states. Reference to a program may encompass the actualinstructions and/or the intent of those instructions.

It should be understood that the foregoing description is onlyillustrative of the present disclosure. Various alternatives andmodifications can be devised by those skilled in the art withoutdeparting from the disclosure. Accordingly, the present disclosure isintended to embrace all such alternatives, modifications and variances.The embodiments described with reference to the attached drawing figuresare presented only to demonstrate certain examples of the disclosure.Other elements, steps, methods, and techniques that are insubstantiallydifferent from those described above and/or in the appended claims arealso intended to be within the scope of the disclosure.

What is claimed is:
 1. A method for controlling electrical treatmentenergy provided to an instrument, the method comprising: providingelectrical treatment energy to the instrument based on an indicatedelectrical energy level; accessing at least one of: voltage signalvalues over time relating to voltage of the electrical treatment energyor current signal values over time relating to current of the electricaltreatment energy; determining whether an arc generated by the instrumentis an arc to be maintained or an arc to be extinguished, based on athreshold value and at least one of: the voltage signal values or thecurrent signal values; and controlling the electrical treatment energybased on determining that the arc is an arc to be extinguished.
 2. Themethod of claim 1, wherein determining whether the arc is an arc to bemaintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a magnitude of change inpeak-to-peak voltage of the electrical treatment energy over time beinggreater than the threshold value, wherein the threshold value changescorresponding to changes in the indicated electrical energy level. 3.The method of claim 1, wherein determining whether the arc is an arc tobe maintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a magnitude of change inpeak-to-peak current of the electrical treatment energy over time beinggreater than the threshold value, wherein the threshold value changescorresponding to changes in the indicated electrical energy level. 4.The method of claim 1, wherein determining whether the arc is an arc tobe maintained or an arc to be extinguished includes determining that thearc is an arc to be extinguished based on a normalized change inpeak-to-peak voltage of the electrical treatment energy over time beinggreater than the threshold value, wherein the normalized change inpeak-to-peak voltage is a ratio of a magnitude of change in peak-to-peakvoltage of the electrical treatment energy over one of: RMS voltage ofthe electrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy, such thatthe threshold value does not change for changes in the indicatedelectrical energy level.
 5. The method of claim 1, wherein determiningwhether the arc is an arc to be maintained or an arc to be extinguishedincludes determining that the arc is an arc to be extinguished based ona normalized change in peak-to-peak current of the electrical treatmentenergy over time being greater than the threshold value, wherein thenormalized change in peak-to-peak current is a ratio of a magnitude ofchange in peak-to-peak current of the electrical treatment energy overone of: RMS voltage of the electrical treatment energy, RMS current ofthe electrical treatment energy, or average power of the electricaltreatment energy, such that the threshold value does not change forchanges in the indicated electrical energy level.
 6. The method of claim1, wherein determining whether the arc is an arc to be maintained or anarc to be extinguished includes: determining a peak-to-peak voltage at afirst time as a difference between a positive voltage peak and anegative voltage peak of the electrical treatment energy at the firsttime; determining a peak-to-peak voltage at a second time as adifference between a positive voltage peak and a negative voltage peakof the electrical treatment energy at a second time, the second timebeing after the first time; determining a change in peak-to-peak voltageas an absolute value of a difference between the peak-to-peak voltage atthe first time and the peak-to-peak voltage at the second time;determining an RMS voltage of the electrical treatment energy and an RMScurrent of the electrical treatment energy for the second time;determining a first normalized change in peak-to-peak voltage as a ratioof the change in peak-to-peak voltage over the RMS voltage; determininga second normalized change in peak-to-peak voltage as a ratio of thechange in peak-to-peak voltage over the RMS current; accessing animpedance value indicative of an impedance of the arc; and determiningthat the arc is an arc to be extinguished when: the first normalizedchange in peak-to-peak voltage is greater than the threshold value andthe impedance value is less than a first impedance threshold, or thesecond normalized change in peak-to-peak voltage is greater than asecond threshold value and the impedance value is less than a secondimpedance threshold.
 7. The method of claim 1, wherein determiningwhether the arc is an arc to be maintained or an arc to be extinguishedincludes determining that the arc is an arc to be extinguished based ona crest factor of the electrical treatment energy being greater than thethreshold value.
 8. The method of claim 1, wherein determining whetherthe arc is an arc to be maintained or an arc to be extinguished includesdetermining that the arc is an arc to be extinguished based on an amountof variation in crest factor of the electrical treatment energy overtime being greater than the threshold value.
 9. The method of claim 1,wherein determining that the arc is an arc to be extinguished includes:determining voltage crest factor values over time based on a ratio ofone of positive voltage peak or negative voltage peak of the electricaltreatment energy over an RMS value of the electrical treatment energy;determining current crest factor values over time based on a ratio ofone of positive current peak or negative current peak of the electricaltreatment energy over an RMS value of the electrical treatment energy;high-pass filtering the voltage crest factor values to provide filteredvoltage crest factor values; high-pass filtering the current crestfactor values to provide filtered current crest factor values; combiningabsolute values of the filtered voltage crest factor values withabsolute values of the filtered current crest factor values to providecombined crest factor values; low-pass filtering the combined crestfactor values to provide resulting values indicative of an amount ofvariation in the voltage crest factor values and the current crestfactor values; and determining that the arc is an arc to be extinguishedwhen the resulting values exceed the threshold value for a time durationthreshold.
 10. An electrosurgical generator for controlling electricaltreatment energy provided to an instrument, the generator comprising:one or more processors; and at least one memory having stored thereoninstructions which, when executed by the one or more processors, causethe generator to: provide electrical treatment energy to the instrumentbased on an indicated electrical energy level; access at least one of:voltage signal values over time relating to voltage of the electricaltreatment energy or current signal values over time relating to currentof the electrical treatment energy; determine whether an arc generatedby the instrument is an arc to be maintained or an arc to beextinguished, based on a threshold value and at least one of: thevoltage signal values or the current signal values; and control theelectrical treatment energy based on determining that the arc is an arcto be extinguished.
 11. The electrosurgical generator of claim 10,wherein the instructions, when executed by the one or more processors,further cause the generator, in determining whether the arc is an arc tobe maintained or an arc to be extinguished, to determine that the arc isan arc to be extinguished based on a magnitude of change in peak-to-peakvoltage of the electrical treatment energy over time being greater thanthe threshold value, wherein the threshold value changes correspondingto changes in the indicated electrical energy level.
 12. Theelectrosurgical generator of claim 10, wherein the instructions, whenexecuted by the one or more processors, further cause the generator, indetermining whether the arc is an arc to be maintained or an arc to beextinguished, to determine that the arc is an arc to be extinguishedbased on a magnitude of change in peak-to-peak current of the electricaltreatment energy over time being greater than the threshold value,wherein the threshold value changes corresponding to changes in theindicated electrical energy level.
 13. The electrosurgical generator ofclaim 10, wherein the instructions, when executed by the one or moreprocessors, further cause the generator, in determining whether the arcis an arc to be maintained or an arc to be extinguished, to determinethat the arc is an arc to be extinguished based on a normalized changein peak-to-peak voltage of the electrical treatment energy over timebeing greater than the threshold value, wherein the normalized change inpeak-to-peak voltage is a ratio of a magnitude of change in peak-to-peakvoltage of the electrical treatment energy over one of: RMS voltage ofthe electrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy, such thatthe threshold value does not change for changes in the indicatedelectrical energy level.
 14. The electrosurgical generator of claim 10,wherein the instructions, when executed by the one or more processors,further cause the generator, in determining whether the arc is an arc tobe maintained or an arc to be extinguished, to determine that the arc isan arc to be extinguished based on a normalized change in peak-to-peakcurrent of the electrical treatment energy over time being greater thanthe threshold value, wherein the normalized change in peak-to-peakcurrent is a ratio of a magnitude of change in peak-to-peak current ofthe electrical treatment energy over one of: RMS voltage of theelectrical treatment energy, RMS current of the electrical treatmentenergy, or average power of the electrical treatment energy, such thatthe threshold value does not change for changes in the indicatedelectrical energy level.
 15. The electrosurgical generator of claim 10,wherein the instructions, when executed by the one or more processors,further cause the generator, in determining whether the arc is an arc tobe maintained or an arc to be extinguished, to: determine a peak-to-peakvoltage at a first time as a difference between a positive voltage peakand a negative voltage peak of the electrical treatment energy at thefirst time; determine a peak-to-peak voltage at a second time as adifference between a positive voltage peak and a negative voltage peakof the electrical treatment energy at a second time, the second timebeing after the first time; determine a change in peak-to-peak voltageas an absolute value of a difference between the peak-to-peak voltage atthe first time and the peak-to-peak voltage at the second time;determine an RMS voltage of the electrical treatment energy and an RMScurrent of the electrical treatment energy for the second time;determine a first normalized change in peak-to-peak voltage as a ratioof the change in peak-to-peak voltage over the RMS voltage; determine asecond normalized change in peak-to-peak voltage as a ratio of thechange in peak-to-peak voltage over the RMS current; access an impedancevalue indicative of an impedance of the arc; and determine that the arcis an arc to be extinguished when: the first normalized change inpeak-to-peak voltage is greater than the threshold value and theimpedance value is less than a first impedance threshold, or the secondnormalized change in peak-to-peak voltage is greater than a secondthreshold value and the impedance value is less than a second impedancethreshold.
 16. The electrosurgical generator of claim 15, wherein theinstructions, when executed by the one or more processors, further causethe generator, in determining whether the arc is an arc to be maintainedor an arc to be extinguished, to determine that the arc is an arc to beextinguished based on a crest factor of the electrical treatment energybeing greater than the threshold value.
 17. The electrosurgicalgenerator of claim 10, wherein the instructions, when executed by theone or more processors, further cause the generator, in determiningwhether the arc is an arc to be maintained or an arc to be extinguished,to determine that the arc is an arc to be extinguished based on anamount of variation in crest factor of the electrical treatment energyover time being greater than the threshold value.
 18. Theelectrosurgical generator of claim 17, wherein the instructions, whenexecuted by the one or more processors, further cause the generator, into determine that the arc is an arc to be extinguished, to: determinevoltage crest factor values over time based on a ratio of one ofpositive voltage peak or negative voltage peak of the electricaltreatment energy over an RMS value of the electrical treatment energy;determine current crest factor values over time based on a ratio of oneof positive current peak or negative current peak of the electricaltreatment energy over an RMS value of the electrical treatment energy;high-pass filter the voltage crest factor values to provide filteredvoltage crest factor values; high-pass filter the current crest factorvalues to provide filtered current crest factor values; combine absolutevalues of the filtered voltage crest factor values with absolute valuesof the filtered current crest factor values to provide combined crestfactor values; low-pass filter the combined crest factor values toprovide resulting values indicative of an amount of variation in thevoltage crest factor values and the current crest factor values; anddetermine that the arc is an arc to be extinguished when the resultingvalues exceed the threshold value for a time duration threshold.
 19. Anelectrosurgical system, comprising: an instrument; and anelectrosurgical generator that includes: one or more processors, and atleast one memory having stored thereon instructions which, when executedby the one or more processors, cause the generator to: provideelectrical treatment energy to the instrument based on an indicatedelectrical energy level; access at least one of: voltage signal valuesover time relating to voltage of the electrical treatment energy orcurrent signal values over time relating to current of the electricaltreatment energy; determine whether an arc generated by the instrumentis an arc to be maintained or an arc to be extinguished, based on athreshold value and at least one of: the voltage signal values or thecurrent signal values; and control the electrical treatment energy basedon determining that the arc is an arc to be extinguished.